Secret test at startup

backend/tests/test_configuration.py

@@ -1,10 +1,36 @@
 import re
 from pathlib import Path
+import pytest
+
+from backend.app.core.config import Settings, validate_configuration
 
 
 ROOT = Path(__file__).resolve().parents[2]
 
 
+def test_production_configuration_rejects_missing_or_default_secret():
+    with pytest.raises(RuntimeError, match='LINKLOG_SECRET_KEY'):
+        validate_configuration(Settings(app_env='production', secret_key='', data_encryption_key=''))
+    with pytest.raises(RuntimeError, match='LINKLOG_SECRET_KEY'):
+        validate_configuration(Settings(app_env='production', secret_key='dev-secret-key-change-me', data_encryption_key=''))
+
+
+def test_production_configuration_rejects_weak_or_missing_encryption_key():
+    with pytest.raises(RuntimeError, match='entropy'):
+        validate_configuration(Settings(app_env='production', secret_key='A' * 32, data_encryption_key=''))
+    with pytest.raises(RuntimeError, match='DATA_ENCRYPTION_KEY'):
+        validate_configuration(Settings(app_env='production', secret_key='A1b2C3d4E5f6G7h8I9j0K1l2M3n4O5p6', data_encryption_key='invalid'))
+
+
+def test_production_configuration_accepts_strong_secrets():
+    values = Settings(
+        app_env='production',
+        secret_key='A1b2C3d4E5f6G7h8I9j0K1l2M3n4O5p6',
+        data_encryption_key='L5M4sQYVjD1N7pT2Xk8R0aBcDeFgHiJkLmNoPqRsTuV=',
+    )
+    validate_configuration(values)
+
+
 def test_production_compose_configuration_matches_settings_environment_keys():
     compose = (ROOT / 'docker-compose.yml').read_text()
     settings = (ROOT / 'backend' / 'app' / 'core' / 'config.py').read_text()